{-# LANGUAGE QuantifiedConstraints #-} {-# LANGUAGE FunctionalDependencies #-} {-# LANGUAGE UndecidableInstances #-} {-# LANGUAGE PolyKinds #-} module Err where import GHC.Exts (Constraint) class Determines b | -> b class (forall (b :: *) (c :: Constraint). (Determines b, Determines c) => c) => OpCode instance OpCode